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DENSIFICATION - FOAM POLYSTYRENE RECYCLING A breakthrough densification technology for Polystyrene Foam #6 cushion and food service packaging is revolutionizing polystyrene foam recycling which until now has been very difficult because of the light density of the foam material. The new densification process yields strong economic and environmental dividends. Foam Polystyrene is highly valued for its use in food packaging to make cups, bowls, plates, trays, clamshells, meat trays and egg cartons; and as protective packaging for shipping electronics and other fragile items. There are two types of Foam Polystyrene; expanded polystyrene used as cushion and transportation packaging; and, extruded polystyrene which is used for food packaging and by the quick service food industry.

Because Foam Polystyrene is so lightweight, composed of 90% air, it offers a number of environmental benefits. It requires less energy and water to manufacture saving resources and reducing air emissions primarily because of its lower weight. A recent Life Cycle Assessment study conducted by Franklin & Associates confirms the environmental benefits over other material options. While 100 percent recyclable, the light density of Foam Polystyrene makes recycling costly and cumbersome. Discarded Foam Polystyrene takes up a lot of space, and is therefore more expensive to ship. But what if we could compress PS foam, squeezing out the air? Now, we can.

A breakthrough green recycling technology – densification – has solved the problem. The densification technology compresses the material squeezing out almost all the air. Removing the air reduces the volume and creates dense, compact solid bricks that are stackable and easy to transport.

The stackable densified blocks can vary in size – 7 inches to 4 feet in length – dependent on the end user needs for reprocessing and shipping requirements.

The typical volume reduction is 20:1. Filled to capacity, a 53-foot semi-truck trailer can carry only slightly more than half a tonne of loose Foam Polystyrene. But loaded with densified material, the same 53-foot truck trailer can carry about 20 tons.

Shipping costs drop 97%. That’s a huge savings – both for the environment and in shipping costs. It’s like taking 35 trucks off the road for every one that remains.

Other Benefits of the Technology

It results in increased revenue for operators as the densified material commands higher prices and broader markets. The global market for post-consumer Foam Polystyrene is estimated to be 120,000 tonnes annually.

It lowers operating costs, and creates local green jobs.

It reduces transportation emissions by up to 80% and diverts plastic resources from landfill.

How It Works 1.	Post-consumer PS foam is collected through either curbside or depot programs. 2.	The material is then sent to the densifier where it is compacted into blocks. 3.	From there, it goes to a recycler. The plastic blocks are re-manufactured into commercially successful products – including high-end picture frames, decorative mouldings and office supplies.

Densifier Technologies

There are a number of different densifier technologies on the market – mechanical, hydraulic, and thermal. Densifiers are available in sizes from ~15 kg/hr to ~ 500 kg/hr

Mechanical Densifiers

A rotating screw is used to compress, shape and discharge densified blocks.

Hydraulic Densifiers

A hydraulic ram is used to compress, shape and discharge densified blocks.

Thermal Densifiers

Heat is used to soften the polystyrene foam and collapse the cell structure.

Need-To-Know Operating Costs

Labour Typically one person operation

Utilities Densifiers – 1.5 to 70 kW Pre-breakers – up to 15 kW Conveyors ~ 1- 3 kW Transfer blowers ~ 3 kW Packaging Pallets, Stretch wrap 24

Need-To-Know Logistics

Densified blocks stacked on pallets provide best truck/container fill.

PS densified to 280 kg/m3 or greater.

Alternative packaging methods (e.g. gaylords) may not be optimum for long distance transportation